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Date: Wed, 11 Oct 2023 16:54:49 +0100
From: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, James Morse
 <james.morse@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Zenghui Yu
 <yuzenghui@huawei.com>, Raghavendra Rao Ananta <rananta@google.com>, Mark
 Rutland <mark.rutland@arm.com>, Will Deacon <will@kernel.org>, James Clark
 <james.clark@arm.com>
Subject: Re: [PATCH 1/2] KVM: arm64: Disallow vPMU for NV guests
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 <20231011081649.3226792-2-oliver.upton@linux.dev>
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On 2023-10-11 09:16, Oliver Upton wrote:
> The existing PMU emulation code is inadequate for use with nested
> virt. Disable the feature altogether with NV until the hypervisor
> controls are handled correctly.

Could you at least mention *what* is missing? Most of the handling
should identical, and the couple of bits what would need to be
handled (such as MDCR_EL2) are not covered by this disabling.

As it is stands, I'm not there is much to be gained from this.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...